Band Offsets at Semiconductor-Oxide Interfaces from Hybrid Density Functional Calculations

Abstract

Band offsets at semiconductor-oxide interfaces are determined through a scheme based on hybrid density functionals, which incorporate a fraction $\alpha$ of Hartree-Fock exchange. For each bulk component, the fraction $\alpha$ is tuned to reproduce the experimental band gap, and the conduction and valence band edges are then located with respect to a reference level. The lineup of the bulk reference levels is determined through an interface calculation, and shown to be almost independent of the fraction $\alpha$. Application of this scheme to the Si-SiO$_2$, SiC-SiO$_2$, and Si-HfO$_2$ interfaces yields excellent agreement with experiment.